UK regulators are warning patients about battery problems with Medtronic’s EnTrust implantable defibrillators. The warning follows a UK recall of the devices just announced by the Medicines and Healthcare products Regulatory Agency (MHRA). Medtronic also issued a Field Safety Notice addressing this problem early last month.

According to UK regulators, the Medtronic EnTrust Implantable Cardioverter Defibrillators (ICDs) could cause early battery depletion, said Mass Device, and recommend patients implanted with these devices check with their physicians and reprogram the EnTrust ICDs so that they beep in the event of a low battery.

The prior Medtronic warning letter also mentioned the Escudo ICDs and noted that under 1% of the global distribution of the two devices may be impacted by an internal short circuit defect that could drain the ICDs’ battery without sufficient warning, said Mass Device.

“Typically, these heart devices have 3 months of normal operation after the device signals the need for replacement,” Medtronic spokeswoman Kathleen Janasz told MassDevice by email. “EnTrust devices may require replacement sooner than expected, and result in less than 3 months of normal operation once the device indicates the need for replacement,” she added.

Some 69,000 patients have received the EnTrust device, said Mass Device. Janasz also said no patient deaths or serious injuries have been reported to Medtronic, to date, over the defect. A Hong Kong regulatory alert issued earlier this month indicated that 51 patients there received the recalled Medtronic ICDs, which are no longer marketed there.

The EnTrust ICDs received U.S. Food and Drug Administration (FDA) premarket approval in 2005; Medtronic ceased manufacturing them in April 2011. The Escudo devices were not sold in the U.S.

As we previously wrote, the MHRA explained that a risk of loss of ICD/pacing therapy, after the elective replacement indicator (ERI) is reached, occurs due to rapid battery depletion after about 2 ½ years following implantation. The Medtronic EnTrust models involved are D153ATG, D153DRG, D153VRC, D154ATG, D154DRG, and D154VRC.

In the event of a battery short circuit, the ICD may be unable to provide the required therapy for the three-month period generally expected post-ERI; however, incidents of charge circuit timeout have occurred.

The rapid voltage drop has been linked to an internal short circuit within the ICD battery; the exact root cause is under investigation by the manufacturer and the issue appears to be specific to EnTrust devices. Failure rate data for other Medtronic ICD models incorporating the same battery model currently indicate that they are not affected. These batteries are not used by other manufacturers

The MHRA previously announced that ICDs should be replaced in cases in which the ERI has been reached when a rapid battery voltage drop took place in the preceding two-week period. Prophylactic replacement of these recalled devices is not recommended, except under exceptional circumstances, said the MHRA.